Purpose: Oral morphine is the first-choice opioid for moderate to severe cancer pain.  Transdermal fentanyl is an alternative in patients with stable requirements for high-potency opioids (HPO) or if drugs cannot be taken orally.  Drug regulatory authorities have issued several alerts to use transdermal fentanyl only for chronic pain and in HPO-tolerant patients to minimise the risk of severe opioid side effects.  The aim of this study was to characterise utilisation of transdermal fentanyl in Germany.

Methods: The analysis was based on data from four German statutory health insurers from the years 2004 to 2006.  Descriptive analyses were performed in new users of transdermal fentanyl to assess HPO-naivety, potential difficulties with the oral route in HPO-naive patients and the number of transdermal fentanyl dispensations.  The initial dose in new users was assessed in 2005 to 2006 after marketing of transdermal fentanyl 12.5 microg/hour.

Results: Of 35,262 patients with new use of transdermal fentanyl, 29,793 (84.5%) were assessed as HPO-naive.  Of these, 21,596 (72.5%) did not have diagnoses indicating difficulties with the oral route.  For 71.2% of the HPO-naive new users of transdermal fentanyl, the first dose exceeded the recommended dose of 12.5 microg/hour, and 49.3% of them received only one prescription of the drug.

Conclusions: Transdermal fentanyl was used as a first-choice opioid, which may increase the risk of serious opioid side effects, in a substantial number of HPO-naive patients.  Inappropriate prescribing included also high initial doses in HPO-naïve patients and possible prescription for acute pain in a considerable proportion of patients.